To determine that might require face-to-face contact and since he is a diagnosed schizophrenic, it might still be unclear.
Even if the racism only comes out during manic periods, it would be difficult to parse that in an online medium. Since very few of us are trained to deal with that sort of episode, it is probably best to avoid the issue entirely.
Just about all Americans exhibit some racism, although most of it manifests itself in the form of less-obvious, but still insidious, biases and so on, rather than calling people the n-word on Hacker News.
